This invention relates to a pneumatic tire having improved performance on a wet road.
When a car runs on a wet road, a coefficient of friction between tires and the wet road surface drops generally. Particularly when the water depth of the wet road surface is great or when a running speed of the car is high, a water layer develops between the tires and the road surface and the coefficient friction drops drastically. Such a state is generally referred to as "hydroplaning".
If hydroplaning occurs, the car cannot be driven any more than an accident will occur. This hydroplaning is likely to occur in the case of flat tires at a high running speed.
Therefore, various attempts have been made to this data to prevent the occurrence of hydroplaning, but none of them are yet entirely satisfactory.